Six cases of rat lungworm reported on Maui

The disease is often spread through contact with a ‘semi-slug’

Chris Sugidono

Staff Writer

csugidono@mauinews.com

A “semi-slug,” carrier of the rat lungworm disease, sticks to a garbage bag last week in Hana. Increasing numbers of the slug appear to be the cause of an outbreak of the disease that may have infected six people on Maui in the past three months.
• KAWIKA KAINA photo

Six cases of rat lungworm have been reported on Maui over the past three months — tripling the amount of cases the island has seen in the past decade, Maui District Health Officer Dr. Lorrin Pang said Tuesday.

Three of the cases are confirmed with a seventh case involving a Maui woman who believes she contracted the parasite on the Big Island, Pang said. The island has only had two cases of the disease, one of which was confirmed in 2010.

The disease is commonly spread through contact with the invasive “semi-slug,” which is prevalent on the Big Island, where the vast majority of cases are reported in Hawaii. Rats host the worm and pass larvae through their feces, which are eaten by the slugs. Humans are then infected after eating raw fruits and vegetables contaminated by the slug.

The infection can cause a rare type of meningitis that causes severe headaches and stiffness of the neck, tingling or painful feelings in the skin or extremities, low-grade fever, nausea and vomiting, according to the state Department of Health Disease Investigation Branch. Temporary paralysis of the face may also occur as well as light sensitivity.

There is no cure for the disease.

“It’s pretty bad,” Pang said of the worm, which attacks the brain and spinal cord. “Some of the damage is permanent.”

Reactions from the parasite vary from person to person, but it appears the Maui woman has one of the worst cases, a friend said. Hana resident Kawika Kaina identified the woman as Tricia Mynar, a teacher at Kamehameha Schools Maui, and said she is experiencing tremendous pain and uses a walker due to the damage from the parasite.

Mynar was born and raised in Hana, and her diagnosis shocked the community, Kaina said.

“Her boss is my dad,” he said. “It really did hit close to home. Just recently a lot of folks in Hana have become more aware of it and a lot more people are finding it in their yard.”

Kaina said many Hana residents have seen the slug near their homes for years, but they figured the slugs were like any other snail. He had no idea how dangerous they are until the state Department of Health sent out a flier a couple weeks ago cautioning residents about recent reports.

“I’ll be honest, my greens intake has definitely dwindled below the five-a-day level,” Kaina said. “That’s not because I don’t like greens, that’s just because we don’t want to eat anything raw.

“I have four children of my own so I’ve definitely shied them away from lettuce.”

Kaina placed slug bait across 9 acres of his property on Tuesday after discovering about a dozen semi-slugs in his ti leaves, pohole (fiddlehead fern) and other plants the day before. He even found a slug in his shower Tuesday morning that may have climbed up the pipes.

“It’s everywhere,” he said. “My paranoia level as far as rat lungworm is really up there.”

Concerns over the slug are due to its high rate of carrying the parasite, which ranges from 70 to 80 percent, Pang said. He said the Cuban slug and African snail, which have been on the island for years, are carriers only 25 percent of the time. Freshwater prawns, crabs and frogs are also carriers of the parasite.

While the semi-slug has existed on the island for years, numbers appear to be increasing as evidenced by the rise in rat lungworm cases, Maui Invasive Species Committee Manager Adam Radford said. Residents have sent photos of the slug recently to confirm its existence, which appears to stretch from Nahiku to Kipahulu, he said.

“Just like any invasive species, I’m certain it’s been there for a while,” Radford said. “When you don’t see it, that’s when it’s insidious.”

Fully grown, the snails are 2 inches long and easily seen, but the slug’s larvae can be microscopic, Radford said. Crews have not seen the snails recently in the field, he said.

“It might look like a spot of dirt on the leaf, but it’s actually riddled with the parasite,” he said.

The best way to ensure fruits, vegetables and raw produce are clear of the parasite is to cook or freeze it, Pang said. Produce can also be cleaned thoroughly.

Kawika, a working supervisor at Hana Store, said the recent outbreak has hurt produce sales with residents being more cautious about raw foods. He said the store normally strips the outer parts off, but has “gone a little closer to the center” to ensure produce is as parasite free as possible.

He added that farmers also are taking a serious hit from the parasite, and residents are concerned about what children are eating at school and graduation parties. Eating raw vegetables is an integral part of the Hawaiian lifestyle in Hana, he said.

“Ever since one of our own got sick, the awareness has just blown up,” he said. “Everybody is watching what they eat.”

People who contracted the disease on Maui do not know exactly how they got it, and there is no “obvious connection” among them all, Pang said. He proposed fighting the parasite by controlling rat and slug populations, as well as keeping a careful eye on what tourists and residents put in their mouths.

Experts are still determining the best way to dispose of the slug, Pang said. Smashing the snail, burying it or even burning it does not deter rats from eating it and restarting the cycle of rat lungworm.

“The slug is easy to kill, but the parasite; it’s not so easy,” he said.

Pang has alerted all Maui County doctors to be suspicious of the disease and administer supportive measures to confirmed cases.

Radford said the slug is no longer eradicable on Maui, and his committee is working with the Health Department, the Hawaii Invasive Species Council and other groups to determine the extent of the problem. There have been about 60 recorded cases of rat lungworm, according to the Health Department.

“The problem isn’t going to go away,” he said. “Our focus is on educating the public and determining the extent through social media and potentially survey.”